This invention relates to an anti-theft system for automotive vehicles.
Several anti-theft systems for automotive vehicles have been proposed e.g. by Japanese Provisional Patent Publications (Kokai) Nos. 60-50050 through 60-50056, according to which, when a driver leaves the vehicle, it is detected whether or not locking of all covering parts which are openable and closable, such as doors, a trunk, and a bonnet (hereinafter merely called "coverings") has been properly effected, and upon the lapse of a certain time period after detection of such locking an alarm permission mode is set up, whereby if a door lock is broken, or any one of the coverings is opened without effecting a predetermined resetting operation for cancelling the alarm permission mode, the alarm is given immediately. Generally, in such systems, the alarm permission mode is cancelled either when it is detected that a door lock is rotated from a locking position to an unlocking position by operation of a proper key, or when it is detected that a locking and unlocking lever of a door lock mechanism is swung in the unlocking direction. Therefore, these conventional systems cannot protect the automotive vehicles from such illegal burglarious conduct such as operation of an indoor lock knob after breakage of a door glass, or forcibly swinging the locking and unlocking lever of the door lock mechanism by means of a wire, etc. which is inserted through a gap between the windowpane of a door and the frame of the door.